In what situations does automatic increase of dynamic array (slice) size occur in programming languages?

In Go, a slice is a structure that contains a pointer to an array, a length, and a capacity. The automatic resizing of a slice occurs when you add elements using the append function, and the current length of the slice reaches its capacity.

At this point, a new array with increased capacity (usually twice the previous one) is allocated, the old elements are copied to the new array, and the slice's pointer is updated to the new array. This allows the slice to grow dynamically as elements are added.

Example:

s := make([]int, 0, 2) // length 0, capacity 2
s = append(s, 1)        // length 1, capacity 2
s = append(s, 2)        // length 2, capacity 2
s = append(s, 3)        // length 3, capacity increased, for example, to 4

Thus, the size increases automatically when elements are added and the length reaches the slice's capacity.